Thermal management system and related methods for vehicle having electric traction motor and range extending device

ABSTRACT

A vehicle, such as a parallel or series hybrid vehicle, includes both an electric traction motor and a range extending device such as, for example, an internal combustion engine, or a fuel cell. In an embodiment, a thermal management system for the vehicle includes a passenger cabin heating circuit configured to circulate heat exchange fluid through a liquid-to-liquid heat exchanger and a passenger cabin heating heat exchanger. A motor circuit can be configured to circulate heat exchange fluid through the electric traction motor, a transmission control module, and a DC/DC converter. The motor circuit can be selectably connected to the passenger cabin heating circuit by a valve. An engine circuit is configured to circulate heat exchange fluid through the internal combustion engine, a radiator, and the liquid-to-liquid heat exchanger. The liquid-to-liquid heat exchanger is configured to transfer heat between heat exchange fluid of the passenger cabin heating circuit and heat exchange fluid of the engine circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 61/623,243 filed Apr. 12, 2012. The above-notedapplication is incorporated in its entirety by reference.

FIELD OF THE INVENTION

The present disclosure relates to vehicles, and, more particularly tovehicles that include both an electric traction motor and a rangeextending device such as, for example, an internal combustion engine, ora fuel cell.

BACKGROUND OF THE INVENTION

Vehicles with electric traction motors offer the promise of poweredtransportation while producing little or no emissions at the vehicle.Some vehicles are powered by electric motors only and rely solely on theenergy stored in an on-board battery pack. Some vehicles are hybrids,having both a traction motor and an internal combustion engine, whichmay, for example, be used to assist the traction motor in driving thewheels (a parallel hybrid), or which may, for example, be used solely tocharge the on-board battery pack, thereby extending the operating rangeof the vehicle (a series hybrid). In some vehicles, there is a single,centrally-positioned electric motor that powers one or more of thevehicle wheels, and in other vehicles, one or more of the wheels have anelectric motor (referred to sometimes as a hub motor) positioned at eachdriven wheel.

While currently proposed and existing hybrid vehicles are advantageousin some respects over vehicles powered solely by internal combustionengines, there are problems that are associated with some hybridvehicles. It would be beneficial to provide technology that improves theefficiency with which power is used in the operation of these vehicles.

SUMMARY OF THE INVENTION

In an aspect, the invention is directed to a vehicle includes anelectric traction motor and a range extending device such as, forexample, an internal combustion engine, or a fuel cell. Heat generatedby each of the electric traction motor and the range extending devicecan be used to heat a passenger cabin of the vehicle. A radiator can beused to cool the electric traction motor and the range extending device.Heat generated by the electric traction motor or by other electricalcomponents of the vehicle can be used to heat battery packs of thevehicle.

In a second aspect, the invention is directed to a thermal managementsystem for a vehicle wherein the system includes a first fluid circuitused to control the temperature of one or more components of the vehiclesuch as, for example, the passenger cabin, components related to abattery pack of the vehicle, power electronics components, an electrictraction motor, or the like. It will be understood that in any givenembodiment the vehicle need not have all these items be controlled bythe first fluid circuit. The system further includes a second fluidcircuit and a range extending device such as, for example, an internalcombustion engine or a fuel cell, that, when operating, heats fluid inthe second fluid circuit. A liquid-to-liquid heat exchanger is providedto transfer heat between the first and second fluid circuits.

In an embodiment of the second aspect, a thermal management system for avehicle is provided including a passenger cabin heating circuitconfigured to circulate heat exchange fluid through a liquid-to-liquidheat exchanger and a passenger cabin heating heat exchanger, and asecond circuit configured to circulate heat exchange fluid through arange extending device (such as, for example, an internal combustionengine, or a fuel cell), a radiator, and the liquid-to-liquid heatexchanger. The liquid-to-liquid heat exchanger is configured to transferheat between heat exchange fluid of the passenger cabin heating circuitand heat exchange fluid of the second circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described, by way of example only,with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a vehicle that includes a thermalmanagement system in accordance with an embodiment of the presentdisclosure;

FIG. 2 is a schematic illustration of a thermal management system forthe vehicle of FIG. 1;

FIG. 3 is a block diagram of a controller for the thermal managementsystem of FIG. 2;

FIG. 4 is a schematic illustration of another embodiment of a thermalmanagement system for the vehicle of FIG. 1;

FIG. 5 is a graph of the temperature of battery packs that are part ofthe vehicle shown in FIG. 1; and

FIGS. 6 a-h show schematic diagrams of heating and coolingconfigurations of the thermal management system.

DETAILED DESCRIPTION OF THE INVENTION

Reference is made to FIG. 1, which shows a vehicle 12. The vehicle 12includes wheels 13, an electric traction motor 14 for driving the wheels13, first and second battery packs 16 a and 16 b, a passenger cabin 18,a high voltage electrical system 20 (FIG. 2), a low voltage electricalsystem, and a range extending device 21 that in this example is aninternal combustion engine 21.

The motor 14 may have any suitable configuration for use in powering thevehicle 12. The motor 14 may be mounted in a motor compartment that isforward of the cabin 18. The motor 14 may be connected to a gearbox (notshown) which drives the wheels 13. The motor 14 is an electricalcomponent that generates heat during use and thus requires cooling. Tothis end, the motor 14 includes a motor fluid flow conduit fortransporting heat exchange fluid (e.g., coolant) about the motor 14, soas to maintain the motor 14 within a suitable temperature range.

The internal combustion engine 21 may also have any suitableconfiguration for use in the vehicle 12. For example, the internalcombustion engine 21 may, for example, be a gasoline engine or it may bea diesel engine. Alternatively other fuels may be used, such as LNG. Theengine 21 could be a reciprocating-type engine, or, for example, it maybe a Wankel (rotary) type engine. The internal combustion engine 21 maybe connected to one or more generators or alternators to generateelectrical power to charge the battery packs 16 a and 16 b. The internalcombustion engine 21 may be known as a range extender. Alternatively,the internal combustion engine 21 may be connected to a drivetrain fordirectly powering the wheels 13. The configuration of the internalcombustion engine 21 with respect to the electric traction motor 14 maydesignate the vehicle 12 as a series or parallel hybrid vehicle. Theinternal combustion engine 21 may be located in the motor compartmentwith the motor 14 or at a different location. The internal combustionengine 21 generates heat during use and thus requires cooling. To thisend, the internal combustion engine 21 includes an engine fluid flowconduit for transporting heat exchange fluid about the internalcombustion engine 21, so as to maintain the internal combustion engine21 within a suitable temperature range.

Reference is made to FIG. 2, which shows a schematic illustration of athermal management system 10 for the vehicle 12. Components forming partof and served by the thermal management system 10 are shown, while othercomponents of the vehicle 12 are omitted for the sake of clarity.

A transmission control module shown at 28 is part of the high voltageelectrical system 20 and is provided for controlling the current flow tohigh voltage electrical loads within the vehicle 12, such as the motor14, an air conditioning compressor 30, a heater 32 and a DC/DC converter34. The transmission control module 28 is an electrical component thatgenerates heat during use and thus has a transmission control modulefluid flow conduit associated therewith for transporting heat exchangefluid about the transmission control module 28, so as to maintain thetransmission control module 28 within a suitable temperature range. Thetransmission control module 28 may be positioned immediately upstreamfluidically from the motor 14.

The DC/DC converter 34 receives current from the transmission controlmodule 28 and converts it from high voltage to low voltage. The DC/DCconverter 34 sends the low voltage current to a low voltage battery (notshown), which is used to power low voltage loads in the vehicle 12. Thelow voltage battery may operate at any suitable voltage, such as 12 V.The DC/DC converter 34 is an electrical component that generates heatduring use and thus has a DC/DC converter fluid flow conduit associatedtherewith for transporting heat exchange fluid about the DC/DC converter34, so as to maintain the DC/DC converter 34 within a suitabletemperature range.

The battery packs 16 a and 16 b send power to the transmission controlmodule 28 for use by the motor 14 and other high voltage loads and thusform part of the high voltage electrical system 20. The battery packs 16a and 16 b may be any suitable types of battery packs. In an embodiment,the battery packs 16 a and 16 b are each made up of a plurality oflithium polymer cells. The battery packs 16 a and 16 b have atemperature range (shown in FIG. 5) in which they are preferablymaintained so as to provide them with a relatively long operating life.While two battery packs 16 a and 16 b are shown, it is alternativelypossible to have any suitable number of battery packs, such as onebattery pack, or three or more battery packs depending on the packagingconstraints of the vehicle 12.

A battery charge control module shown at 42 is provided and isconfigured to connect the vehicle 12 to an external electrical source(e.g., a 110 V source or a 220 V source) shown at 44, and to send thecurrent received from the electrical source 44 to any of severaldestinations, such as, the battery packs 16 a and 16 b, the transmissioncontrol module 28 and the low voltage battery. The battery chargecontrol module 42 generates heat during use and thus requires cooling.To this end, the battery charge control module 42 includes a batterycharge control module fluid flow conduit for transporting fluid aboutthe battery charge control module 42 so as to maintain the batterycharge control module 42 within a suitable temperature range,

A heating, ventilation, and air conditioning (HVAC) system 46 isprovided for controlling the temperature of the passenger cabin 18 (FIG.1). The HVAC system 46 is configured to be capable of both cooling andheating the cabin 18. To achieve this, the HVAC system 46 may includeone or more heat exchangers, such as a passenger cabin heating heatexchanger 47 and a passenger cabin cooling heat exchanger 48 (which maybe referred to as evaporator 48). The cabin heating heat exchanger 47has a heat exchange fluid inlet 49 and a heat exchange fluid outlet 50and is used to heat an air flow that is passed into the cabin 18. Thecabin cooling heat exchanger 48 includes a refrigerant inlet 51 and arefrigerant outlet 52, and is used to cool an air flow that is passedinto the cabin 18.

The motor 14, the engine 21, the transmission control module 28, theDC/DC converter 34, the battery packs 16 a and 16 b, the battery chargecontrol module 42, and the HVAC system 46 constitute thermal loads onthe thermal management system 10.

The thermal management system 10 includes a motor circuit 56, a secondor engine circuit 57, a cabin heating circuit 58, a battery circuit 60and a main cooling circuit 62.

The motor circuit 56 is configured for cooling the traction motor 14,the transmission control module 28, and the DC/DC converter 34, whichconstitute a motor circuit thermal load 61. The motor circuit thermalload 61 has a motor circuit thermal load inlet 63 and a motor circuitthermal load outlet 65. The motor circuit 56 includes a first motorcircuit conduit 66 fluidically between a cabin heating circuit valve 88and the motor circuit thermal load inlet 63, a second motor circuitconduit 68 fluidically between the motor circuit thermal load outlet 65and the cabin heating circuit valve 88, and a motor circuit pump 70positioned to pump heat exchange fluid through the motor circuit 56.

The motor circuit pump 70 may be positioned anywhere suitable, such asin the first motor circuit conduit 66. The motor circuit pump 70 may bea variable-speed electric pump.

The elements that make up the motor circuit thermal load 61 may bearranged in any suitable way. For example, the DC/DC converter 34 may bedownstream from the pump 70 and upstream from the transmission controlmodule 28, and the motor 14 may be downstream from the transmissioncontrol module 28. Thus, the inlet to the DC/DC converter 34 constitutesthe thermal load inlet 63 and the motor outlet constitutes the thermalload outlet 65.

A motor circuit temperature sensor 76 is provided for determining thetemperature of heat exchange fluid at a selected point in the motorcircuit 56. As an example, the motor circuit temperature sensor 76 maybe positioned downstream from the motor circuit thermal load 61, so asto sense the highest temperature of the heat exchange fluid.

The engine circuit 57 is configured for cooling the internal combustionengine 21, which constitutes an engine circuit thermal load 67 that hasan engine circuit thermal load inlet 69 and an engine circuit thermalload outlet 71. The engine circuit 57 includes a first engine circuitconduit 73 fluidically between a heat exchanger 99 and the enginecircuit thermal load inlet 69, a second engine circuit conduit 77fluidically between the engine circuit thermal load outlet 71 and aradiator 64, a third engine circuit conduit 81 fluidically between theradiator 64 and the heat exchanger 99, and a second or engine circuitpump 79 positioned to pump heat exchange fluid through the enginecircuit 57.

The engine circuit pump 79 may be positioned anywhere suitable, such asin the second engine circuit conduit 77. The engine circuit pump 79 maybe a variable-speed electric pump.

Additional elements may be included in the engine circuit thermal load67, and these may be arranged relative to the engine 21 in any suitableconfiguration.

Additionally, a fourth engine circuit conduit 74 may be providedfluidically between the second and third engine circuit conduits 77 and81, so as to permit the flow of heat exchange fluid to bypass theradiator 64. To control whether the flow of heat exchange fluid isdirected through the radiator 64 or through the fourth engine circuitconduit 74, a radiator bypass valve 75 is provided and may be positionedin the second engine circuit conduit 77. The radiator bypass valve 75 iscontrollable so that in a first position it directs the flow of heatexchange fluid to the radiator 64 through the second engine circuitconduit 77 and in a second position it directs the flow of heat exchangefluid to the third engine circuit conduit 81 through the fourth enginecircuit conduit 74, so as to bypass the radiator 64. By permitting thetemperature of the heat exchange fluid to rise, the engine can moreeasily reach an operating temperature at which its emissions arerelatively low and its combustion efficiency is relatively high.Furthermore, flow through the fourth engine circuit conduit 74 may insome embodiments be easier than flow through the radiator 64 (i.e.,there is less of a pressure drop associated with flow through the fourthconduit 74 than there is with flow through the radiator 64), and sobypassing the radiator 64 whenever possible reduces the energyconsumption of the pump 79 and of the thermal management system 10.Furthermore, bypassing the radiator 64 may permit the fan (shown at 144)to be kept off, which further reduces the energy consumption of thethermal management system 10.

When the radiator bypass valve 75 is in its first position, all of theheat exchange fluid flow is directed through the second conduit 77,through the radiator 64, and through the third conduit 81. Conversely,when the radiator bypass valve 75 is in its second position, all of theheat exchange fluid flow is directed through the fourth conduit 74 andinto the third conduit 81 towards the heat exchanger 99. There can be nobackflow from the fourth conduit 74 into the radiator 64 because of thefluid already present between the radiator 64 and the fourth conduit 74.Thus, using only a single valve (i.e., the bypass valve 75) provides thecapability of selectably bypassing the radiator 64, instead of using onevalve at the junction of the second and fourth conduits 77 and 74 andanother valve at the junction of the third and fourth conduits 81 and74.

As a result of using one valve (i.e., valve 75) instead of two valves,the engine circuit 57 contains fewer components, thereby making it lessexpensive, simpler to make and operate, and more reliable. Furthermore,by eliminating one valve, the energy required to move the heat exchangefluid through the engine circuit 57 is reduced, thereby reducing theenergy consumed by the pump 79 and extending the range of the vehicle12.

An engine circuit temperature sensor 83 is provided for determining thetemperature of heat exchange fluid at a selected point in the enginecircuit 57. As an example, the engine circuit temperature sensor 83 maybe positioned downstream from the engine circuit thermal load 67 toprovide an indication of the temperature of the engine 21. Based on thistemperature, a controller 78 (FIG. 3) can determine whether or not toposition the radiator bypass valve 75 in its first position or secondposition.

The cabin heating circuit 58 is configured for providing heated heatexchange fluid to the HVAC system 46 and more specifically to the cabinheating heat exchanger 47, which constitutes the cabin heating circuitthermal load. The cabin heating circuit 58 includes a first cabinheating circuit conduit 80 fluidically between the second motor circuitconduit 68 and the cabin heating heat exchanger inlet 49 (which in theembodiment shown is the inlet to the cabin heating circuit thermalload), and a second cabin heating circuit conduit 82 fluidically betweenthe cabin heating circuit heat exchanger outlet 50 (which in theembodiment shown is the outlet from the cabin heating circuit thermalload) and the first motor circuit conduit 66. In the embodiment shown,the second cabin heating circuit conduit 82 extends to the valve 88 atthe first motor circuit conduit 66.

In some situations the heat exchange fluid will not be sufficiently hotto meet the demands of the HVAC system 46. For such situations, theheater 32 which may be referred to as the cabin heating circuit heater32 is provided in the first cabin heating circuit conduit 80. The cabinheating circuit heater 32 may be any suitable type of heater, such as anelectric heater that is one of the high voltage electrical componentsfed by the transmission control module 28.

A third cabin heating circuit conduit 84 may be provided between thesecond and first cabin heating circuit conduits 82 and 80. A cabinheating circuit pump 86 is provided in the third conduit 84. In somesituations it will be desirable to circulate heat exchange fluid throughthe cabin heating circuit 58. For example, when the fluid is beingheated by the heater 32, it may be advantageous to not transfer thefluid to the motor circuit 56 since the fluid in the motor circuit 56 isused for cooling the motor circuit thermal load 61, and it thus may beundesirable to introduce hot fluid into the motor circuit 56. For thepurpose of preventing heat exchange fluid from being transferred betweenthe cabin heating circuit 58 and the motor circuit 56, the cabin heatingcircuit valve 88 is provided. In the embodiment shown, the cabin heatingcircuit valve 88 is positioned in the second motor circuit conduit 68and is selectably positionable in a first position wherein the valve 88directs fluid flow towards the first motor circuit conduit 66 throughthe second motor circuit conduit 68, and a second position wherein thevalve 88 directs fluid flow towards the cabin heater heat exchanger 47through the first cabin heating circuit conduit 80.

When the cabin heating circuit valve 88 is in the second position, thepump 86 may operate at a selected low flow rate to prevent the fluidflow from short circuiting the cabin heating circuit by flowing backthrough the third conduit 84 towards the second conduit 82.

It will be noted that separation of the fluid flow through the cabinheating circuit 58 and the motor circuit 56 is achieved using a singlevalve (i.e., valve 88), which is positioned at the junction of thesecond motor circuit conduit 68 and the first cabin heating circuitconduit 80. When the valve 88 is positioned in the first position, fluidis directed back into the motor circuit 56 via the first motor circuitconduit 66. There is no net flow out of the cabin heating circuit 58since there is no flow into the cabin heating circuit 58. When the valve88 is positioned in the second position and the pump 86 is off, fluid isdirected through the cabin heating circuit 58 and back into the motorcircuit 56. When the valve 88 is positioned in the first position andthe pump 86 is on, there is no net flow out of the second cabin heatingcircuit conduit 82 as noted above, however, the pump 86 generates afluid circuit loop and drives fluid in a downstream portion 90 of thefirst cabin heating circuit conduit 80, through the cabin heating heatexchanger 47, and through an upstream portion 92 of the second cabinheating circuit conduit 82, whereupon the fluid is drawn back into thepump 86. Because this feature is provided using a single valve (i.e.,valve 88), as opposed to using one valve at the junction of the firstcabin heating circuit conduit 80 and the motor circuit 56 and anothervalve at the junction of the second cabin heating circuit conduit 82 andthe motor circuit 56, the thermal management system 10 is made simplerand less expensive, and it further saves energy consumption by havingfewer valves in the system 10 so as to reduce the energy required by thepump 70 to pump liquid through such valves.

Additionally, the valve 88 combined with the pump 86 permits isolatingheat exchange fluid in the cabin heating circuit 58 from heat exchangefluid in the motor circuit 56, thereby preventing fluid that has beenheated in the cabin heating circuit heater 32 from being sent to themotor circuit 56.

A cabin heating circuit temperature sensor 94 may be provided fordetermining the temperature of the fluid in the cabin heating circuit58. The temperature sensor 94 may be positioned anywhere suitable, suchas downstream from the heat exchanger 99. The temperature sensor 94 maycommunicate with the controller 78 so that the controller 78 candetermine whether or not to carry out certain actions. For example,using the temperature sensed by the temperature sensor 94, thecontroller 78 can determine whether the heater 32 should be activated tomeet the cabin heating demands of the HVAC system 46 as requested by aclimate control system.

The heat exchanger 99 is part of both the cabin heating circuit 58 andthe engine circuit 57. Regarding the cabin heating circuit 58, the heatexchanger 99 is located in the first cabin heating circuit conduit 80,upstream of the heater 32. Regarding the engine circuit 57, the heatexchanger 99 is located between the third engine circuit conduit 81 andthe first engine circuit conduit 73, downstream of the radiator 64. Theheat exchanger 99 can be liquid-to-liquid heat exchanger that allowsheat transfer between the heat exchange fluid in the cabin heatingcircuit 58 and the heat exchange fluid in the engine circuit 57, whilepreventing communication (i.e., mixing) of heat exchange fluid betweenthe cabin heating circuit 58 and the engine circuit 57.

The battery circuit 60 is configured for controlling the temperature ofthe battery packs 16 a and 16 b and the battery charge control module42, which together make up the battery circuit thermal load 96. Athermal load inlet is shown at 98 upstream from the battery packs 16 aand 16 b and a thermal load outlet is shown at 100 downstream from thebattery charge control module 42. The battery packs 16 a and 16 b are inparallel in the battery circuit 60, which permits the fluid flow to eachof the battery packs 16 a and 16 b to be selected individually so thateach battery pack 16 a or 16 b receives as much fluid as necessary toachieve a selected temperature change. A valve for adjusting the flow offluid that goes to each battery pack 16 a and 16 b during use of thethermal management system 10 may be provided, so that the fluid flow canbe adjusted to meet the instantaneous demands of the battery packs 16 aand 16 b. After the fluid has passed through the battery packs 16 a and16 b, the fluid is brought into a single conduit which passes throughthe battery charge control module 42. While the battery packs 16 a and16 b are shown in parallel in the battery circuit 60, they could beprovided in series in an alternative embodiment.

A first battery circuit conduit 102 extends between the second motorcircuit conduit 68 and the battery circuit thermal load inlet 98. Asecond battery circuit conduit 104 extends between the thermal loadoutlet 100 and the first motor circuit conduit 66. A battery circuitpump 106 may be provided for pumping fluid through the battery circuit60 in situations where the battery circuit 60 is isolated from the motorcircuit 56. A battery circuit heater 108 is provided in the firstconduit 102 for heating fluid upstream from the battery circuit thermalload 96 in situations where the battery circuit thermal load 96 requiresit. The battery circuit heater 108 may operate on current from a lowvoltage current source, such as the low voltage battery.

A third battery circuit conduit 110 may be provided fluidically betweenthe second and first battery circuit conduits 102 and 104 so as topermit the flow of heat exchange fluid in the battery circuit 60 to beisolated from the flow of heat exchange fluid in the motor circuit 56. Achiller 112 may be provided in the third conduit 110 for cooling fluidupstream from the thermal load 96 when needed.

A battery circuit valve 114 is provided in the second conduit 104 and ispositionable in a first position wherein the flow of fluid is directedtowards the first motor circuit conduit 66 and in a second positionwherein the flow of fluid is directed into the third battery circuitconduit 110 towards the first battery circuit conduit 102.

It will be noted that the flow in the battery circuit 60 is isolatedfrom the flow in the motor circuit 56 by only one valve (i.e., valve114). When the valve 114 is in the second position, so as to directfluid flow through the third conduit 110 into the first conduit 102,there is effectively no flow from the first motor circuit 56 through thefirst conduit 102 since the loop made up of the downstream portion ofthe first conduit 102, the thermal load 96, the second conduit 104, andthe third conduit 110 is already full of fluid. By using only one valve(i.e., valve 114) to isolate the battery circuit 60, the amount ofenergy consumed by the pump 106 to pump fluid around the battery circuit60 is reduced relative to a similar arrangement using two valves.Additionally, by using only one valve the battery circuit is simpler(i.e., it has fewer components), which reduces its cost and which couldincrease its reliability.

A battery circuit temperature sensor 116 is provided for sensing thetemperature of the fluid in the battery circuit 60. The temperaturesensor 116 may be positioned anywhere in the battery circuit 60, such asin the second conduit 104 downstream from the thermal load 96. Thetemperature from the temperature sensor 116 can be sent to thecontroller 78 to determine whether the valve 114 should be in the firstor second position and whether any devices (e.g., the chiller 112, theheater 108) need to be operated to adjust the temperature of the fluidin the first conduit 102.

The main cooling circuit 62 is provided for assisting in the thermalmanagement of the thermal loads in the HVAC system 46 and the batterycircuit 60. More particularly, the thermal load in the HVAC system 46 isshown at 118 and is made up of the cabin cooling heat exchanger 48(i.e., the evaporator 48).

The components of the main cooling circuit 62 that are involved in thecooling and management of the refrigerant flowing therein include thecompressor 30 and a condenser 122. A first cooling circuit conduit 126extends from the condenser 122 to a point where the conduit 126 dividesinto a first branch 128 which leads to the HVAC system 46 and a secondbranch 130 which leads to the battery circuit 60. A second coolingcircuit conduit 132 has a first branch 134 that extends from the HVACsystem 46 to a joining point and a second branch 136 that extends fromthe battery circuit 60 to the joining point. From the joining point, thesecond cooling circuit conduit 132 extends to the inlet to thecompressor 30.

At the first branch 128 of the first conduit 126 is a flow control valve138 which controls the flow of refrigerant into the cabin cooling heatexchanger 48. The first branch 134 of the second conduit 132 isconnected to the refrigerant outlet from the heat exchanger 48. It willbe understood that the valve 138 could be positioned at the first branch134 of the second conduit 132 instead. The valve 138 is controlled bythe controller 78 and is opened when refrigerant flow is needed throughthe evaporator 48.

At the second branch 130 of the first conduit 126 is a flow controlvalve 140 which controls the flow of refrigerant into the batterycircuit chiller 112. The second branch 136 of the second conduit 132 isconnected to the refrigerant outlet from the chiller 112. It will beunderstood that the valve 140 could be positioned at the second branch136 of the second conduit 132 instead. The valve 140 is controlled bythe controller 78 and is opened when refrigerant flow is needed throughthe chiller 112.

The valves 138 and 140 may be any suitable type of valves with anysuitable type of actuator. For example, they may be solenoidactuated/spring return valves. Additionally, thermostatic expansionvalves shown at 139 and 141 may be provided downstream from the valves138 and 140.

A refrigerant pressure sensors 142 and 143 may be provided anywheresuitable in the cooling circuit 62, such as between the compressor 30and the condenser 122 and upstream of the compressor 30 in the secondconduit 132. The pressure sensors 142 and 143 communicate pressureinformation from the cooling circuit 62 to the controller 78 to assistin controlling the cooling circuit 62.

A fan shown at 144 is provided for blowing air on the radiator 64 andthe condenser 122 to assist in cooling and condensing the heat exchangefluid and the refrigerant respectively. The fan 144 is a variable-speedfan that is controlled by the controller 78.

Expansion tanks 124 a and 124 b are provided for removing gas that canaccumulate in components of the motor circuit 56 and engine circuit 57.The expansion tank 124 a serves the motor circuit 56, and has an inletconnected to the transmission control module 28 and the second batterycircuit conduit 104 and an outlet connected to the first motor circuitconduit 66. The expansion tank 124 b serves the engine circuit 57, andhas an inlet connected to the radiator 64 and an outlet connected to thefirst engine circuit conduit 73. The expansion tank 124 a is positionedat or above the highest elevation of any fluid-carrying component of themotor circuit 56 and battery circuit 60. The expansion tank 124 b ispositioned at or above the highest elevation of any fluid-carryingcomponent of the engine circuit 57. The expansion tank 124 a may be usedas point of entry for heat exchange fluid into the motor circuit 56 andthe battery circuit 60. The expansion tank 124 b may be used as point ofentry for heat exchange fluid into the engine circuit 57. In thisembodiment, separate expansion tanks 124 a and 124 b are used, insteadof a single common tank, because the motor and battery circuits 56 and60 are fluidically isolated from the engine circuit 57. Accordingly, theexpansion tanks 124 a and 124 b may contain different types or differentconcentrations of heat exchange fluid.

FIG. 3 illustrates the controller 78 electrically connected tocontrollable and sensing components of the thermal management system 10.The controller 78 can be electrically connected to these components byway of, for example, conductive wires. A bus, such as controller areanetwork (CAN) bus, may also be used.

The controller 78 is described functionally as a single unit, howeverthe controller 78 may be made up of a plurality of units thatcommunicate with each other. The controller 78 includes at least oneprocessor 166 that can execute instructions originating from memory 168in the form of a program or routine, for example. Such instructions formlogic that can be used by the controller 78 to control the thermalmanagement system 10, as will now be described with reference to variousconfigurations of controllable components of the thermal managementsystem 10 described above. The term configuration as used in thisdisclosure refers to one or more settings of one or more components,such as the positions of valves, the speeds of pumps and fans, thecurrent supplied to heaters, among others.

Also shown in FIG. 3 is an ambient temperature sensor 180 that can beprovided to the vehicle 12 at a position to sense a temperature of theenvironment around the vehicle 12.

The controller 78 can control the temperature of the motor circuitthermal load 61 by controlling the motor circuit pump 70 and the cabinheating circuit valve 88. The motor circuit thermal load 61 can becooled by positioning the cabin heating circuit valve 88 in its secondposition to circulate heat exchange fluid between the motor circuit 56and the cabin heating circuit 58. The cabin heating circuit pump 86 canbe controlled to be off, and the flow rate of heat exchange fluid can becontrolled by the motor circuit pump 70. Waste heat from the motorcircuit thermal load 61 is thus used to heat the passenger cabin 18 viathe cabin heating heat exchanger 47. If no further heat is needed forthe cabin 18 (aside from the waste heat captured from the motor circuitthermal load 61), the heater 32 can remain off, thereby saving energy.Cooling the motor circuit thermal load 61 by heating the cabin 18 inthis way may be referred to as a motor waste-heat recoveryconfiguration.

The controller 78 can further control the temperature of the motorcircuit thermal load 61 by further controlling components of the enginecircuit 57, namely, the radiator bypass valve 75, the radiator fan 144,the engine circuit pump 79, and optionally, the internal combustionengine 21. As in the motor waste-heat recovery configuration, theheating circuit valve 88 may be positioned in its second position tocirculate heat exchange fluid between the motor circuit 56 and the cabinheating circuit 58 using the motor circuit pump 70. The motor circuitthermal load 61 can then be cooled by running the engine circuit pump 79and positioning the radiator bypass valve 75 in its first position toallow heat exchange fluid in the engine circuit 58 to cool at theradiator 64 before entering the heat exchanger 99 to cool heat exchangefluid flowing through the connected cabin heating circuit 58 and motorcircuit 56. The motor circuit thermal load 61 is thus cooled by theradiator 64 via the heat exchanger 99. The fan 144 can be controlled toincrease the cooling capacity of the radiator 64, and thus further coolheat exchange fluid on the motor circuit side of the heat exchanger 99.Cooling the motor circuit thermal load 61 using the radiator 64 in thisway may be referred to as a motor-radiator cooling configuration. Thecontroller 78 can also refrain from turning on the internal combustionengine 21 to temporarily prevent the engine 78 from generating heat thatwould reduce the amount of cooling available to motor circuit thermalload 61. Alternatively, instead of keeping the internal combustionengine 21 off in the motor-radiator cooling configuration, thecontroller 78 can opportunistically enter the motor-radiator coolingconfiguration when the internal combustion engine 21 is off for otherreasons and then exit the motor-radiator cooling configuration when theinternal combustion engine 21 turns on. However, the motor-radiatorcooling configuration can cool the motor circuit thermal load 61 whilethe internal combustion engine 21 is running, though the amount ofcooling provided will be less than when the engine 21 is off, all otherfactors being equal.

The controller 78 can isolate the motor circuit thermal load 61 from thecabin heating circuit 58 to avoid cooling the motor circuit thermal load61 and/or for other reasons. This can be achieved by the controller 78positioning the heating circuit valve 88 in its first position toisolate the motor circuit 56 from the cabin heating circuit 58. This maybe referred to as a motor closed-loop configuration.

The controller 78 can select one of the above-described configurationsfor the motor circuit thermal load 61 with reference to a temperaturesensed by the motor circuit temperature sensor 76. When the temperatureof heat exchange fluid sensed by the motor circuit temperature sensor 76reaches an upper threshold (e.g., 50 degrees Celsius), the controller 78may be programmed to start cooling the motor circuit thermal load 61.When the temperature drops below a lower threshold (e.g., 46 degreesCelsius) the controller 78 may be programmed to stop cooling the motorcircuit thermal load 61. When cooling is not required and there is nocabin heating demand, then the controller 78 has the valve 88 in thefirst position so that the motor circuit 56 is in the motor closed-loopconfiguration.

When cooling is required, the controller 78 can select the motorwaste-heat recovery configuration or the motor-radiator coolingconfiguration based on one or more conditions that can include theamount, if any, of cabin heating being requested by the climate controlsystem and a temperature sensed by the engine circuit temperature sensor83. For example, if no or low cabin heating is being requested and thetemperature sensed by the engine circuit temperature sensor 83 is lowenough (e.g., 45 degrees Celsius) to allow the engine circuit 57 to coolthe motor circuit thermal load 61, then the controller 78 can select themotor-radiator cooling configuration to cool the motor circuit thermalload 61 via the radiator 64. If significant cabin heating is beingrequested, then the controller 78 can select the motor waste-heatrecovery configuration to use heat that would otherwise be wasted toheat the passenger cabin 18 via the cabin heating heat exchanger 47.

The controller 78 can control the temperature of the engine circuitthermal load 67 by controlling the engine circuit pump 79, the radiatorbypass valve 75, and the radiator fan 144. The engine circuit thermalload 67 is cooled using both the radiator 64 and the heat exchanger 99,in an engine-radiator cooling configuration, or just using the heatexchanger 99, in an engine waste-heat recovery configuration, asdetermined by the position of the radiator bypass valve 75. Thecontroller 78 can reference the temperature sensed by the engine circuittemperature sensor 83 to determine the amount of cooling required by theengine circuit thermal load 67. Accordingly, the controller 78 canincrease the cooling effect of the radiator 64 by increasing the speedof the radiator fan 144. The controller 78 can decrease cooling to theengine circuit thermal load 67 by controlling the radiator bypass valve75 to be in its second position so that flow of heat exchange fluidbypasses the radiator 64 and is cooled only at the heat exchanger 99.Bypassing the radiator 64 can be particularly effective when there issignificant cabin heating demand, as heat from the engine circuitthermal load 67 can be imparted to the cabin heating circuit 58 via theheat exchanger 99. The controller 78 can specifically commence theengine waste-heat recovery configuration to increase heat provided tothe heat exchanger 99 in response to cabin heating demand.

The controller 78 can coordinate cooling of the motor circuit thermalload 61 and the engine circuit thermal load 67, with reference to thedemand placed on the cabin heating heat exchanger 47 for cabin heating.The aforementioned configurations can be coordinated as follows.

The motor waste-heat recovery configuration and the engine waste-heatrecovery configuration can be used independently or together to meet thecabin heating demand and save energy in the form of heat that wouldotherwise be dissipated to the surrounding environment. The waste-heatrecovery configurations can be used together, as heat exchange fluidheated by the motor circuit thermal load 61 can be heated further by theengine circuit thermal load 67 via the heat exchanger 99, since theengine 21 is expected to normally operate at temperatures higher thanthose at which the motor 14 normally operates. However, it may bedesirable to avoid using the waste-heat recovery configurations togetherin situations where the engine circuit thermal load 67 would end upheating the motor circuit thermal load 61.

The motor closed-loop configuration can be used with either the enginewaste-heat recovery configuration or the engine-radiator coolingconfiguration. When the motor circuit 56 is in the motor closed-loopconfiguration, the motor circuit 56 is isolated from the cabin heatingcircuit 58 and, accordingly, any heating of the heat exchange fluid inthe cabin heating circuit 58 can only be a result of operation of theheat exchanger 99 and the heater 32.

The motor-radiator cooling configuration is used with theengine-radiator cooling configuration to allow heat from the motorcircuit thermal load 61 to be dissipated at the radiator 64.

It should be noted that the heat exchanger 99 can be used to transferheat in different directions depending on the configuration selected bythe controller 78. For example, when the engine waste-heat recoveryconfiguration is being used to heat the passenger cabin 18, the heatexchanger 99 transfers heat from the engine circuit 57 to the cabinheating circuit 58. When the motor-radiator cooling configuration isbeing used to cool the motor circuit thermal load 61, the heat exchanger99 may transfer heat from the cabin heating circuit 58 to the enginecircuit 57 if the engine 21 is off or in general if the engine circuitthermal load is cold 67.

Regarding cabin heating, the controller 78 responds to a heating demandindicated by the cabin climate control system, which can includebuttons, dials, or any other suitable human-machine interface throughwhich the operator of the vehicle can select how much heat, if any,should be provided to the passenger cabin 18. The controller 78 candetermine whether any one or more of the motor waste-heat recoveryconfiguration, the engine waste-heat recovery configuration, and thecabin heating circuit heater 32 should be used to meet the heatingdemand. The controller 78 can be configured to prioritize use of thewaste-heat recovery configurations over use of the heater 32 in order tosave energy. Which one or more of the waste-heat recovery configurationsis selected can be based, at least in part, on the level of cabinheating demand and the ability of each of the waste-heat recoveryconfigurations to meet the demand, as indicated by the temperaturessensed at sensors 76 and 83.

The controller 78 may have one cabin cooling configuration. Thecontroller 78 determines if the actual temperature of the evaporator 48is higher than the target temperature of the evaporator 48 by more thana calibrated amount. If so, then the controller 78 can turn on thecompressor 30 and move the refrigerant flow control valve 138 to theopen position so that refrigerant flows through the evaporator 48 tocool an air flow that is passed into the cabin 18. The controller 78 canadjust the speed of the compressor 30 based on the states of the flowcontrol valves 138 and 140. The controller 78 can also cycle open andclosed each of the flow control valves 138 and 140 to controlrefrigerant flow.

When the climate control system in the cabin 18 is set to a ‘defrost’setting, the controller 78 will enter a defrost configuration, and willreturn to whichever heating or cooling configuration it was in oncedefrost is no longer needed.

The controller 78 can maintain the temperature of the battery packs 16 aand 16 b within a range that promotes efficiency and extends the life ofthe battery packs 16 a and 16 b. An example of such as range is 36 to 38degrees Celsius. To maintain the battery packs 16 a and 16 b within thistemperature range, the controller 78 can cool or heat the battery packs16 a and 16 b, as will now be discussed.

The controller 78 may have two cooling configurations for cooling thebattery circuit thermal load 96: cooling via the motor circuit 56 andcooling via the chiller 112. As a condition for cooling the batterycircuit thermal load 96, the controller 78 determines whether thetemperature sensed by the battery circuit temperature sensor 116temperature exceeds an upper threshold (e.g., 38 degrees Celsius).

When cooling is required, the controller 78 determines whether the motorcircuit 56 can be used to cool the battery circuit thermal load 96.Accordingly, the controller 78 determines whether the temperature sensedby the motor circuit temperature sensor 76 is lower than a lowerthreshold (e.g., 36 degrees Celsius) by a specific amount (e.g., 1degree Celsius), which may, for example, be related to the expectedtemperature rise that would be incurred in the flow of fluid from thetemperature sensor 76 to the battery circuit thermal load 96. If thetemperature sensed by the motor circuit temperature sensor 76 is lowenough, the controller 78 commences a first battery circuit coolingconfiguration, wherein the controller 78 positions the battery circuitvalve 114 in its first position so that flow of heat exchange fluid isgenerated through the battery circuit 60 from the motor circuit 56, andthe controller 78 puts the refrigerant flow control valve 140 in theclosed position preventing refrigerant flow through the chiller 112.Further, the controller 78 can commence the motor-radiator coolingconfiguration or the motor waste-heat recovery configuration, so thatthe first battery circuit cooling configuration ultimately uses theradiator 64 or the cabin heating heat exchanger 47 to cool the batterycircuit thermal load 96 via the motor circuit 56. When the motorwaste-heat recovery configuration is used, heat from the battery circuitthermal load 96 is used to heat the passenger cabin 18, thereby savingthe energy that would have been used by the heater 32 to heat the cabin18.

When the controller 78 determines that the temperature sensed by themotor circuit temperature sensor 76 is not lower than the lowerthreshold (e.g., 36 degrees Celsius) by the specific amount (e.g., 1degree Celsius), the controller determines that the motor circuit 56cannot be used to cool the battery circuit thermal load 96 effectively.Accordingly, the controller 78 commences a second battery circuitcooling configuration, wherein the controller 78 positions the batterycircuit valve 114 in the second position and turns on the pump 106, sothat flow in the battery circuit 60 is isolated from flow in the motorcircuit 56. The controller 78 additionally positions the flow controlvalve 140 in the open position so that refrigerant flows through thechiller 112 to cool the flow in the battery circuit 60.

Using the motor circuit 56, and ultimately the radiator 64 or cabinheating heat exchanger 47, to cool the battery circuit thermal load 96can reduce the need to use the relatively more energy-expensive chiller112 for this purpose, and as such can conserve energy. Accordingly, thecontroller 78 can be configured to favor the first battery circuitcooling configuration when permitted by other operations in the thermalmanagement system 10.

It will be understood that in any of the battery circuit coolingconfigurations, the controller 78 turns off the battery circuit heater108.

The controller 78 may have four heating configurations for heating thebattery circuit thermal load 96: heating by the motor circuit 56,heating by the battery circuit heater 108, heating by the motor circuit56 and the battery circuit heater 108, and heating by the engine circuit58 via the cabin heating circuit 58 and motor circuit 56. As a conditionfor heating the battery circuit thermal load 96, the controller 78determines whether the temperature sensed by the battery circuittemperature sensor 116 temperature is lower than a lower threshold, suchas the same lower threshold referenced for cooling (e.g., 36 degreesCelsius).

When heating is required, the controller 78 determines whether the motorcircuit 56 can be used to heat the battery circuit thermal load 96.Accordingly, the controller 78 determines whether the temperature sensedby the motor circuit temperature sensor 76 is higher than an upperthreshold (e.g., 38 degrees Celsius) by a specific amount (e.g., 1degree Celsius), which may, for example, be related to the expectedtemperature drop of the fluid as it flows from the temperature sensor 76to the battery circuit thermal load 96. The upper threshold for heatingcan be the same as the upper threshold for cooling, or it can bedifferent. If the temperature sensed by the motor circuit temperaturesensor 76 is high enough, the controller 78 commences a first batterycircuit heating configuration, wherein the controller 78 positions thebattery circuit valve 114 in its first position so that flow of heatexchange fluid is generated through the battery circuit 60 from themotor circuit 56. Additionally, the controller 78 turns off the batterycircuit heater 32. The controller 78 can further operate the motorcircuit 56 in any of its configurations based on considerations of thoseconfigurations. For instance, when in the motor waste-heat recoveryconfiguration, at least some of the heat that would be destined for thecabin 18 is used to heat the battery circuit thermal load 96. When inthe motor-radiator cooling configuration, heating the battery circuitthermal load 96 can increase the speed at which the motor circuitthermal load 61 is cooled. Lastly, the motor circuit closed-loopconfiguration used in conjunction with the first battery circuit heatingconfiguration provides an additional way to cool the motor circuitthermal load 61 in circumstances, for example, in which the motorwaste-heat recovery configuration and motor-radiator coolingconfiguration are less desirable to use.

In a situation where the engine 21 is off, the controller 78 determinesthat the battery packs 16 require heating, and the controller 78determines that the fluid in the motor circuit 56 would not be useful,then the controller 78 may be programmed to use the battery circuitheater 108 to heat fluid circulating in the battery circuit 60 so as toheat the battery circuit thermal load 96. Thus, in this case, thecontroller 78 commences the battery circuit heating configurationwherein the controller 78 positions the battery circuit valve 114 in thesecond position and turns on the pump 106, so that flow in the batterycircuit 60 is isolated from the cooler flow in the motor circuit 56. Thecontroller 78 additionally turns on the battery circuit heater 108 toheat the flow in the battery circuit 60. Since the battery circuit 60 isisolated from the motor circuit 56, the configuration of the motorcircuit 56 need not be considered.

If the controller 78 determines that the motor circuit 56 is not hotenough to heat the battery circuit thermal load 96 to an acceptabletemperature by itself, but can still contribute to heating the batterycircuit thermal load 96 because it is hotter than the battery circuitthermal load 96, the controller 78 can use both the motor circuit 56 andthe battery circuit heater 108 to heat the battery circuit thermal load96 to an acceptable temperature. In this case, the controller 78operates in a third battery circuit heating configuration wherein thecontroller 78 positions the battery circuit valve 114 in the firstposition, so that fluid flows between from the motor circuit 56 throughthe battery circuit 60 and back into the motor circuit 56. In addition,the controller 78 turns on the battery circuit heater 108. Since themotor circuit thermal load 61 is only partially contributing to heatingthe battery circuit thermal load 96, it may in some instances bedesirable to use the third battery circuit heating configuration inconjunction with the motor circuit closed-loop configuration, so thatother sources of cooling (i.e., the cabin heating heat exchanger 47 andthe radiator 64) will not simultaneously pull heat from the motorcircuit thermal load 61.

The fourth battery circuit heating configuration can be used in somesituations, including a situation where fluid in the motor circuit 56 isnot hot enough to heat the battery packs 16 to an acceptable temperaturebut the engine circuit thermal load 67 is sufficiently hot that it canbe used to heat the battery packs 16 to an acceptable temperature. Inthe fourth battery circuit heating configuration, the motor and enginecircuits 56 and 57 are put in their waste-heat recovery configurations,so that the motor circuit 56 is in communication with the heat exchanger99 and so that the engine circuit 57 bypasses the radiator 64.Additionally, the battery circuit valve 114 is positioned in its firstposition to join the motor circuit 56 and the battery circuit 60. Sincethe fluid in the engine circuit 57 is hotter than the fluid in the motorcircuit 56, heat will flow across the heat exchanger 99 from the enginecircuit 57 to the motor circuit 56 (via the heat exchanger 99) to heatthe heat exchange fluid in the motor circuit 56, which will then becirculated through the battery circuit 60 to heat the battery circuitthermal load 96 (and the battery packs 16 in particular). Thus, wasteheat from the engine circuit 57 can be transferred to the batterycircuit thermal load 96 via the heat exchanger 99, the cabin heatingcircuit 58, and the motor circuit 56. Using waste heat from the enginecircuit 57 can save energy by reducing the need to use the batteryheater 108. One consideration that the controller 78 can take intoaccount when determining whether the fourth battery circuit heatingconfiguration should be used over the second battery circuit heatingconfiguration, is the amount, if any, of cabin heating demand, which mayrequire that all or most of the waste heat from the engine circuit 57 beused to heat the passenger cabin 18 rather than the battery circuitthermal load 96.

It will be understood that in any of the battery circuit heatingconfigurations, the controller 78 turns off the chiller 112.

Heating and cooling configurations for the motor circuit 56, the enginecircuit 57, the cabin heating circuit 58, and the battery circuit 60,including those discussed above, are shown schematically in FIGS. 6 a-h.FIGS. 6 a-h indicate the positions of the valves 75, 88, and 114, aswell as the general expected tendency of heat flow among the motorcircuit 56, the engine circuit 57, the cabin heating circuit 58, and thebattery circuit 60, as indicated by arrows, at least in some situations.Double-headed arrows indicate that in some situations the flow of heatis in one direction (i.e. from a first circuit to a second circuit) andin other situations the flow of heat is the reverse (i.e. from thesecond circuit to the first circuit). No arrow indicates no appreciableheat flow. The heat flows represented in FIGS. 6 a-h are based onsituations wherein the pumps 70, 79, 86, and 106 operate as discussedabove and that heaters 32 and 108 are not operated.

Moreover, as mentioned above, the first position of valve 88 isolatesthe motor circuit 56 from the cabin heating circuit 58, while the secondposition of valve 88 connects the motor circuit 56 to the cabin heatingcircuit 58. The first position of the valve 75 connects the radiator 64to the engine circuit 57, while the second position of the valve 75bypasses the radiator 64. Finally, the first position of the valve 114connects the battery circuit 60 to the motor circuit 56, while thesecond position of the valve 114 isolates the battery circuit from themotor circuit 56.

FIGS. 6 a-h illustrate generally expected heat flows for illustrativepurposes in certain situations, however the heat flows may be differentunder certain circumstances.

FIG. 6 a shows the first or third battery circuit heating configurationheating the battery packs 16 a and 16 b with the motor circuitclosed-loop configuration or the first battery circuit coolingconfiguration cooling the battery packs 16 a and 16 b with the motorcircuit closed-loop configuration, depending on the relativetemperatures of the motor circuit 56 and battery circuit 60. FIG. 6 aalso shows a configuration in which the engine circuit 57 can heat orcool the cabin heating circuit 58 via the heat exchanger 99 depending onthe relative temperatures of these circuits 57 and 58.

FIG. 6 b shows the motor circuit closed-loop configuration, as well asthe configuration of FIG. 6 a in which the engine circuit 57 can heat orcool the cabin heating circuit 58.

FIG. 6 c shows the first or third battery circuit heating configurationheating the battery packs 16 a and 16 b with the motor circuitclosed-loop configuration or the first battery circuit coolingconfiguration cooling the battery packs 16 a and 16 b with the motorcircuit closed-loop configuration, depending on the relativetemperatures of the motor circuit 56 and battery circuit 60. FIG. 6 calso shows the engine waste-heat recovery configuration being used toheat the passenger cabin 18.

FIG. 6 d shows the motor circuit closed-loop configuration, as well asthe engine waste-heat recovery configuration being used to heat thepassenger cabin 18.

FIG. 6 e shows the motor-radiator cooling configuration, as well as thefirst or third battery circuit heating configuration.

FIG. 6 f shows the motor-radiator cooling configuration.

FIG. 6 g shows the fourth battery circuit heating configuration usingthe engine waste-heat recovery configuration to heat the battery packs16 a and 16 b.

FIG. 6 h shows the engine waste-heat recovery configuration as well asthe motor waste-heat recovery configuration. The direction of heat flowbetween the motor circuit 56 and the cabin heating circuit 58 depends onthe heating demand at the cabin 18.

The logic used by the controller 78 to control the operation of thethermal management system 10 can be configured to depend on which ofseveral states the vehicle is in. The vehicle 12 may be on-plug and off,which means that the vehicle itself is off (e.g., the ignition key isout of its slot in the instrument panel) and is plugged into theexternal electrical source 44 (e.g., for recharging the battery packs 16a and 16 b). The vehicle may be off-plug and off, which means that thevehicle itself is off and is not plugged into the external electricalsource 44. The vehicle may be off-plug and on, which means that thevehicle itself is on and is not plugged into the external electricalsource 44. The controller 78 can take into account the on-plug oroff-plug state of the vehicle when determining which of theabove-described heating or cooling configurations to use. For example,when the vehicle 12 is on-plug and off, the motor circuit thermal load61 is not expected to significantly increase in temperature, so thecontroller 78 may not need to consider using the motor-radiator coolingconfiguration.

In some embodiments, the vehicle may lack the capability to be pluggedinto an external electrical source for charging the battery. In suchembodiments, the vehicle would charge the battery via the engine 21. Insuch embodiments the vehicle would never therefore be on-plug.

In the event of an emergency battery shutdown, the controller 78 may beprogrammed to shut off the compressor 30 and turn on the cabin heatingcircuit heater 32 so as to bleed any residual voltage.

Reference is made to FIG. 4, which shows a schematic illustration of athermal management system 200 for a vehicle 12 in accordance withanother embodiment of the present invention. Features and aspects of theother embodiments described herein can be used with this embodiment.Like reference numerals (i.e., identical numerals and those that areidentical when ignoring the leading “2”) denote like elements. Redundantdescription is omitted for clarity. The description of the otherembodiments can be referenced for like elements.

A power electronics cooling circuit 256 includes the DC/DC converter 34and the transmission control module 28, which generate heat duringoperation and thus form an power electronics cooling circuit thermalload 261. The conduits 66 and 68, the pump 70, and the valve 88 arearranged as discussed above, except that an power electronics coolingcircuit thermal load outlet 265 is located at the transmission controlmodule 28. The power electronics cooling circuit 256 does not includethe electric traction motor 14, although the motor 14 is stillelectrically connected to the transmission control module 28 to drivethe vehicle 12.

The electric traction motor 14 joins the internal combustion engine 21in a second or engine-motor circuit 257. The motor 14 and engine 21 forman engine-motor thermal load 267 with an engine-motor circuit thermalload inlet 269 at the motor 14. In this embodiment, the motor 14 ispositioned upstream of the engine 21, so that the motor 14 receives heatexchange fluid that is cooler than that provided to the engine 21. Thisis because the motor 14 has a lower maximum acceptable workingtemperature, which can, for example, be about 100 degrees Celsius withtemporary excursions up to 140 degrees Celsius permitted.

The controller 78 can use the heating and cooling configurations asdescribed for the embodiment shown in FIG. 2, with the followingdifferences. The motor waste-heat recovery configuration described inrelation to FIG. 2, may be referred to as the power electronicswaste-heat recovery configuration in relation to FIG. 4. In thisconfiguration, waste heat from the DC/DC converter 34 and thetransmission control module 28 is used to heat the cabin 18 via thecabin heating heat exchanger 47. The motor-radiator coolingconfiguration described above may be referred to as the powerelectronics-radiator cooling configuration in relation to FIG. 4.wherein the heat exchanger 99 draws heat from the power electronicscooling circuit 256 via the cabin heating circuit 58 to ultimately bedissipated at the radiator 64. The motor closed-loop configuration maybe referred to as the power electronics closed-loop configuration inrelation to FIG. 4, wherein the power electronics cooling circuit 256 isisolated from the cabin heating circuit 58. The engine waste-heatrecovery configuration described above may be referred to as theengine-motor waste-heat recovery configuration in relation to FIG. 4,wherein waste heat from both the engine 21 and the motor 14 is used toheat the cabin via the heat exchangers 99 and 47. The engine-radiatorcooling configuration may be referred to as the engine-motor radiatorcooling configuration in relation to FIG. 4, in which the engine 21 andmotor 14 are both cooled using the radiator 64. Regarding theseconfigurations, the example temperature thresholds may be the same asdescribed for the embodiment of FIG. 2, or they may be different. FIGS.6 a-h also apply to this embodiment.

An advantage of including the motor 14 in the same heat exchange fluidcircuit as the engine 21 is that the motor 14 can withstand highertemperatures than the DC/DC converter 34 and the transmission controlmodule 28. The motor 14 has a maximum acceptable operating temperature(e.g., about 100 degrees Celsius) that is closer to the normal operatingtemperature of the engine 21 (e.g., about 120 degrees Celsius) than tothe maximum acceptable operating temperature (e.g., about 75 degreesCelsius) of the DC/DC converter 34 and transmission control module 28.

In any of the embodiments, the controller 78 can be programmed with thefollowing high-level objectives and strategies for using the abovedescribed configurations. The high level objectives include:

A. control the components related to heating and cooling of the batterycircuit thermal load 96 to maintain the battery packs 16 a and 16 b andthe battery charge control module 42 within the optimum temperaturerange during charging and vehicle operation;

B. maintain the motor 14, the transmission control module 28 and theDC/DC converter 34 at their optimum temperature ranges;

C. control the components related to heating and cooling the cabin 18based on input from the climate control system;

D. operate with a goal of maximizing vehicle range while meeting vehiclesystem requirements;

E. maintain the engine 21 in its optimum temperature range; and

F. use waste heat from the motor 14 and the engine 21 to heat thepassenger cabin 18.

The controller 78 may use the following high-level strategy on-plug:

When the vehicle is on-plug and is off, the controller 78 pre-conditionsthe battery packs 16 a and 16 b if required. Pre-conditioning entailsbringing the battery packs 16 a and 16 b into a temperature rangewherein the battery packs 16 a and 16 b are able to charge more quickly.

The controller 78 determines the amount of power available from theexternal electrical source for temperature control of the battery packs16 a and 16 b, which is used to determine the maximum permittedcompressor speed, maximum fan speed or the battery pack heatingrequirements depending on whether the battery packs 16 a and 16 brequire cooling or heating. A calibratible hysteresis band will enablethe battery pack temperature control to occur in a cyclic manner if thebattery pack temperatures go outside of the selected limits (which areshown in FIG. 5). If sufficient power is available from the electricalsource, the battery packs 16 a and 16 b may be charged whilesimultaneously being conditioned (i.e., while being cooled or heated toremain within their selected temperature range). If the battery packs 16a and 16 b reach their fully charged state, battery pack conditioningmay continue, so as to bring the battery packs 16 a and 16 b to theirselected temperature range for efficient operation.

When the vehicle is on-plug the battery circuit heater 108 may be usedto bring the battery packs 16 a and 16 b up to a selected temperaturerange, as noted above. In one of the heating configurations describedabove for the battery circuit 60, the battery circuit valve 114 is inthe second position so that the flow in the battery circuit 60 isisolated from the flow in the motor circuit 56, and therefore thebattery circuit heater 108 only has to heat the fluid in the batterycircuit 60.

The cabin may be pre-conditioned (i.e., heated or cooled while thevehicle is off) when the vehicle is on-plug and the state of charge ofthe battery packs 16 a and 16 b is greater than a selected value.

If the vehicle is started while on-plug, the controller 78 may continueto condition the battery packs 16 a and 16 b, to cool the motor circuitthermal load 61 and use of the HVAC system 46 for both heating andcooling the cabin 18 may be carried out.

When the vehicle is off-plug, battery pack heating may be achievedsolely by using the heat in the fluid from the motor circuit (i.e.,without the need to activate the battery circuit heater 108). Thus,while the vehicle is off-plug and on and the battery packs 16 a and 16 brequire heating, the battery circuit valve 114 may be in the firstposition so that the battery circuit 60 is not isolated from the motorcircuit 56. Some flow may pass through the third battery circuit conduit110 for flow balancing purposes, however the refrigerant flow to thechiller 112 is prevented while the battery packs 16 a and 16 b requireheating. By using low-voltage battery circuit heaters instead ofhigh-voltage heaters for the heaters 108, a weight-savings is achievedwhich thereby extends the range of the vehicle.

When the vehicle is off-plug, battery pack cooling may be achieved byisolating the battery circuit 60 from the motor circuit 56 by moving thebattery circuit valve 114 to the second position and by opening the flowof refrigerant to the chiller 112 by moving the flow control valve 140to its open position, and by running the compressor 30, as describedabove in one of the two cooling configurations for the battery circuit60.

It will be noted that the battery packs 16 a and 16 b may sometimesreach different temperatures during charging or vehicle operation. Thecontroller 78 may at certain times request isolation of the batterycircuit 60 from the motor circuit 56 and may operate the battery circuitpump 106 without operating the heater 108 or permitting refrigerant flowto the chiller 112. This will simply circulate fluid around the batterycircuit 60 thereby balancing the temperatures between the battery packs16 a and 16 b.

Reference is made to FIG. 5, which shows a graph of battery packtemperature vs. time for a particular example of a battery pack, tohighlight several of the rules which the controller 78 (FIG. 3) followsin certain embodiments. In situations where the vehicle is on-plug andthe battery packs 16 a and 16 b are below a selected minimum chargingtemperature Tcmin (FIG. 5), the controller 78 will heat the batterypacks 16 a and 16 b prior to charging them. Once the battery packs 16 aand 16 b reach the minimum charging temperature Tcmin, some of the powerfrom the electrical source may be used to charge the battery packs 16 aand 16 b, and some of the power from the electrical source may continueto be used to heat them. When the battery packs 16 a and 16 b reach aminimum charge only temperature Tcomin, the controller 78 may stop usingpower from the electrical source to heat the battery packs 16 a and 16 band may thus use all the power from the electrical source to chargethem. Tcmin may be, for example, −35 degrees Celsius and Tcomin may be,for example, −10 degrees Celsius.

While charging, the controller 78 may precondition the battery packs 16a and 16 b for operation of the vehicle. Thus, the controller 78 maybring the battery packs 16 a and 16 b to a desired minimum operatingtemperature Tomin while on-plug and preferably during charging.

In situations where the vehicle is on-plug and the battery packs 16 aand 16 b are above a selected maximum charging temperature Tcmax, thecontroller 78 will cool the battery packs 16 a and 16 b prior tocharging them. Once the battery packs 16 a and 16 b come down to themaximum charging temperature Tcmax power from the electrical source maybe used to charge them, while some power may be required to operate thecompressor 30 and other components in order to maintain the temperaturesof the battery packs 16 a and 16 b below the temperature Tcmax. Tcmaxmay be, for example, 30 degrees Celsius.

The battery packs 16 a and 16 b may have a maximum operating temperatureTomax that is the same or higher than the maximum charging temperatureTcmax. As such, when the battery packs 16 a and 16 b are cooledsufficiently for charging, they are already pre-conditioned foroperation. In situations where the maximum operating temperature Tomaxis higher than the maximum charging temperature Tcmax, the temperaturesof the battery packs 16 a and 16 b may be permitted during operationafter charging to rise from the temperature Tcmax until they reach thetemperature Tomax.

The maximum and minimum operating temperatures Tomax and Tomin define apreferred operating range for the battery packs 16 a and 16 b. Insituations where the battery packs 16 a and 16 b are below minimumoperating temperature or above their maximum operating temperature, thevehicle may still be used to some degree. Within selected first rangesshown at 150 and 152 (based on the nature of the battery packs 16 a and16 b) above and below the preferred operating range the vehicle maystill be driven, but the power available will be somewhat limited.Within selected second ranges shown at 154 and 156 above and below theselected first ranges 150 and 152, the vehicle may still be driven in alimp home mode, but the power available will be more severely limited.Above and below the selected second ranges, the battery packs 16 a and16 b cannot be used. The lower first range 150 may be between about 10degrees Celsius and about −10 degrees Celsius and the upper first range152 may be between about 35 degrees Celsius and about 45 degreesCelsius. The lower second range 154 may be between about −10 degreesCelsius and about −35 degrees Celsius. The upper second range may bebetween about 45 degrees Celsius and about 50 degrees Celsius.

An advantage of the thermal management systems 10 and 200 is that theyare readily adaptable to vehicles originally designed to use onlyinternal combustion engines. That is, existing internal combustionengine vehicle designs can be reconfigured as hybrid designs by, forexample, replacing the larger, original internal combustion engine withthe smaller, range-extending engine 21, adding the motor 14, batterypacks 14 a and 14 b, and their supporting components, adding the cabinheater 32 and heat exchanger 99, and adding an additional expansion tank124 a. The HVAC system 46, compressor 30, and condenser 122, radiator64, and fan 144 package can all remain as originally designed. This canlead to more efficient use of existing design and manufacturingresources.

It will be noted that the pumps 70, 79, 86 and 106 are preferablyvariable flow rate pumps. In this way they can be used to adjust theflow rates of the heat exchange fluid through the circuits 56, 57, 58,and 60. By controlling the flow rate generated by the pumps 70, 79, 86and 106, the amount of energy expended by the thermal management system10 can be adjusted in relation to the level of criticality of the needto change the temperature in one or more of the thermal loads.

Additionally, the compressor 30 is also capable of variable speedcontrol so as to meet the variable demands of the HVAC system 46 and thebattery circuit 60.

Throughout this disclosure, the controller 78 is referred to as turningon devices (e.g., the battery circuit heater 108, the chiller 112),turning off devices, or moving devices (e.g., valve 88) between a firstposition and a second position. It will be noted that, in somesituations, the device will already be in the position or the statedesired by the controller 78, and so the controller 78 will not have toactually carry out any action on the device. For example, it may occurthat the controller 78 determines that the battery heater 108 needs tobe turned on. However, the heater 108 may at that moment already be onbased on a prior decision by the controller 78. In such a scenario, thecontroller 78 obviously does not actually ‘turn on’ the heater 108, eventhough such language is used throughout this disclosure. For thepurposes of this disclosure and claims, the concepts of turning on,turning off and moving devices from one position to another are intendedto include situations wherein the device is already in the state orposition desired and no actual action is carried out by the controller78 on the device.

In this disclosure the use of an evaporator was described for coolingthe air flow to the cabin 18 and a chiller was described for cooling thecoolant in the battery circuit. It will be understood that the chilleris a first heat exchanger and may be replaced by any other suitable typeof heat exchanger, (e.g. a different type of heat exchanger that stilluses refrigerant), and similarly the evaporator is a second heatexchanger and may be replaced by any other suitable type of heatexchanger, (e.g. a different type of heat exchanger that still usesrefrigerant).

In addition, terms such as heat, heating, cool, and cooling are used inthis disclosure to describe the transfer of heat. Use of one term overanother is not intended to be limiting, and heating in one direction canbe taken to be equivalent to cooling in the opposite direction.

According to one aspect of this disclosure, a method of heating avehicle passenger cabin of a vehicle includes heating heat exchangefluid with an electric traction motor of the vehicle, heating heatexchange fluid with a range extending device (such as, for example, aninternal combustion engine or a fuel cell) of the vehicle, providingheat from the heat exchange fluid heated by the electric traction motorto a passenger cabin heating heat exchanger, providing heat from theheat exchange fluid heated by the range extending device to thepassenger cabin heating heat exchanger.

Providing heat from the heat exchange fluid heated by the rangeextending device to the passenger cabin heating heat exchanger caninclude using a liquid-to-liquid heat exchanger to transfer heat fromthe heat exchange fluid heated by the range extending device to heatexchange fluid flowing to the passenger cabin heating heat exchanger.

The heat exchange fluid flowing to the passenger cabin heating heatexchanger can include the heat exchange fluid heated by the electrictraction motor.

The heat exchange fluid heated by the range extending device can includethe heat exchange fluid heated by the electric traction motor.

Providing heat from the heat exchange fluid heated by the electrictraction motor and the range extending device to the passenger cabinheating heat exchanger can include using a liquid-to-liquid heatexchanger to transfer heat from the heat exchange fluid heated by theelectric traction motor and the int range extending device to heatexchange fluid flowing to the passenger cabin heating heat exchanger.

The method can further include heating heat exchange fluid with at leastone of a transmission control module and a DC/DC converter of thevehicle, and providing heat from the heat exchange fluid heated by theat least one of the transmission control module and the DC/DC converterto the passenger cabin heating heat exchanger.

According to another aspect of this disclosure, a method of coolingelectrical components of a vehicle includes circulating heat exchangefluid through a circuit including a range extending device (such as, forexample, an internal combustion engine or a fuel cell), a radiator, anda liquid-to-liquid heat exchanger. The method further includes coolingthe circulating heat exchange fluid using the radiator, cooling heatexchange fluid heated by at least one of a transmission control moduleand a DC/DC converter using the liquid-to-liquid heat exchanger,circulating the heat exchange fluid cooled by the liquid-to-liquid heatexchanger through the at least one of the transmission control moduleand the DC/DC converter.

The method can further include cooling heat exchange fluid heated by anelectric traction motor using the liquid-to-liquid heat exchanger, andcirculating the heat exchange fluid cooled by the liquid-to-liquid heatexchanger through the electric traction motor.

The circuit can further include an electric traction motor.

According to another aspect of this disclosure, a thermal managementsystem for a vehicle includes a passenger cabin heating circuitconfigured to circulate heat exchange fluid through a liquid-to-liquidheat exchanger and a passenger cabin heating heat exchanger. The thermalmanagement system further includes a second circuit configured tocirculate heat exchange fluid through a range extending device (such as,for example, an internal combustion engine or a fuel cell), a radiator,and the liquid-to-liquid heat exchanger. The liquid-to-liquid heatexchanger is configured to transfer heat between heat exchange fluid ofthe passenger cabin heating circuit and heat exchange fluid of thesecond circuit.

The system can further include a motor circuit configured to circulateheat exchange fluid through an electric traction motor. The motorcircuit can be selectably connected to the passenger cabin heatingcircuit by a valve.

The system can further include a battery circuit configured to circulateheat exchange fluid through a battery pack. The battery circuit can beselectably connected to the motor circuit by another valve.

The motor circuit can be further configured to circulate heat exchangefluid through at least one of a transmission control module and a DC/DCconverter.

The system can further include an power electronics cooling circuitconfigured to circulate heat exchange fluid through at least one of atransmission control module and a DC/DC converter. The power electronicscooling circuit can be selectably connected to the passenger cabinheating circuit by a valve.

The second circuit can be further configured to circulate heat exchangefluid through an electric traction motor.

The system can further include a cabin heating circuit pump positionedat the cabin heating circuit.

The system can further include a second pump positioned at the secondcircuit.

According to another aspect of this disclosure, a method of heating abattery pack of a vehicle having an electric traction motor is provided.The method includes heating heat exchange fluid with a range extendingdevice (such as, for example, an internal combustion engine or a fuelcell) of the vehicle, providing heat from the heat exchange fluid heatedby the range extending device to a heat exchanger, and transferring heatusing the heat exchanger to heat exchange fluid circulating through abattery circuit coupled to the battery pack.

The method can further include heating the heat exchange fluidcirculating through a battery circuit using the electric traction motor.

For greater certainty, throughout this disclosure, where an internalcombustion engine has been described it will be understood that someother range extending device could be used instead, such as, forexample, a fuel cell.

While the above description constitutes a plurality of embodiments ofthe present disclosure, it will be appreciated that the presentdisclosure is susceptible to further modification and change withoutdeparting from the fair meaning of the accompanying claims.

1. A method of heating a vehicle passenger cabin of a vehicle, themethod comprising: a) heating heat exchange fluid with an electrictraction motor of the vehicle and with a range extending device of thevehicle; and b) heating the vehicle passenger cabin using the heatexchange fluid.
 2. The method of claim 1, wherein the heat exchangefluid is a first heat exchange fluid, and step a) includes: c) heating asecond heat exchange fluid with the range extending device; and d)heating the first heat exchange fluid with the second heat exchangefluid.
 3. The method of claim 2, wherein step d) includes passing thefirst and second heat exchange fluids through a liquid-to-liquid heatexchanger.
 4. The method of claim 1, wherein the heat exchange fluidflows through the motor and through the range extending device.
 5. Themethod of claim 4, wherein the heat exchange fluid is a first heatexchange fluid, and wherein step a) includes: f) heating a second heatexchange fluid with the motor and with the range extending device; andg) heating the first heat exchange fluid with the second heat exchangefluid.
 6. The method of claim 1, further comprising: i) heating the heatexchange fluid with at least one of a transmission control module of thevehicle and a DC/DC converter of the vehicle; and j) heating the vehiclepassenger cabin using the heat exchange fluid.
 7. The method of claim 1,wherein the range extending device is an internal combustion engine. 8.A thermal management system for a vehicle, the system comprising: apassenger cabin heating circuit configured to circulate heat exchangefluid through a liquid-to-liquid heat exchanger and a passenger cabinheating heat exchanger; and a second circuit configured to circulateheat exchange fluid through a range extending device, a radiator, andthe liquid-to-liquid heat exchanger, wherein the liquid-to-liquid heatexchanger is configured to transfer heat between heat exchange fluid ofthe passenger cabin heating circuit and heat exchange fluid of thesecond circuit.
 9. The system of claim 8, further comprising a motorcircuit configured to circulate heat exchange fluid through an electrictraction motor, the motor circuit being selectably connected to thepassenger cabin heating circuit by a cabin heating circuit valve. 10.The system of claim 9, further comprising a battery circuit configuredto circulate heat exchange fluid through a battery pack, the batterycircuit being selectably connected to the motor circuit by a batterycircuit valve.
 11. The system of claim 9, wherein the motor circuit isfurther configured to circulate heat exchange fluid through at least oneof a transmission control module and a DC/DC converter.
 12. The systemof claim 8, further comprising a power electronics cooling circuitconfigured to circulate heat exchange fluid through at least one of atransmission control module and a DC/DC converter, the power electronicscooling circuit being selectably connected to the passenger cabinheating circuit by a cabin heating circuit valve.
 13. The system ofclaim 8, wherein the second circuit includes an electric traction motor.14. The system of claim 8, further comprising a cabin heating circuitpump positioned to circulate heat exchange fluid through the cabinheating circuit.
 15. The system of claim 8, further comprising a secondpump positioned at the second circuit.
 16. The system of claim 8,wherein the range extending device is an internal combustion engine. 17.A method of heating a battery pack of a vehicle having an electrictraction motor, the method comprising: heating heat exchange fluid witha range extending device of the vehicle; providing heat from the heatexchange fluid heated by the range extending device to a heat exchanger;and transferring heat using the heat exchanger to heat exchange fluidcirculating through a battery circuit that includes the battery pack.18. The method of claim 17, further comprising heating the heat exchangefluid circulating through a battery circuit using the electric tractionmotor.
 19. The method of claim 17, wherein the range extending device isan internal combustion engine.